The present invention generally relates to image processing apparatuses, and more particularly to an image processing apparatus in which an area of a document is designated by a marking entered in the document and a portion encircled by the marking is treated as a marked area which is the subject of a trimming or a masking process.
There are strong demands for image processing apparatuses having an editing function such as trimming and masking. For example, there are demands for a copying machine which makes copy prints by extracting only a desired region of a document or masking (erasing) the desired region of the document. There are also demands for a facsimile machine which transmits an image of only a desired region of the document. In such kinds of image processing apparatuses, a detection of the desired region which is designated plays a most important role of the image processing.
In a trimming mode, a trimming of a predetermined region of a document image means that only an image portion corresponding to the predetermined region is extracted from the entire document image. On the other hand, in a masking mode, a masking of the predetermined region of the document image means that the image portion corresponding to the predetermined region is masked and only an image portion other than the image portion corresponding to the predetermined region is extracted from the entire document image.
Conventionally, in these kinds of image processing apparatuses, the desired region of the document is generally designated by one of following first and second methods. According to the first method, the desired region is designated from ten-keys of an operation part by entering coordinates of the desired region. On the other hand, according to the second method, the document is once read into and displayed on a CRT display device and the desired region is designated by moving a cursor, a light pen, a mouse and the like while monitoring the document image.
According to the first method, the operation of reading the coordinates of the desired region of the document and the operation of entering the coordinates from the ten-keys of the operation part are troublesome to perform. In addition, the desired region which can be designated is substantially limited to a region having a simple shape such as a rectangular region.
On the other hand, according to the second method, the image processing apparatus becomes complex, bulky and expensive. Furthermore, it is impossible to carry out the image processing in real time, thus making the apparatus unsuited for use in a copying machine, a facsimile machine and the like which are generally used in offices.
In order to reduce the problems of the above described methods, an apparatus was proposed in a Japanese Published Patent Application No. 60-33333. According to this proposed apparatus, the desired region of the document is detected from an L-shaped indication of a predetermined color entered on the document. Hence, it is possible to designate the desired region of the document when the L-shaped indication of the predetermined color is entered on the document to indicate the desired region. However, because the L-shaped indication uses two adjacent sides of a rectangle, the shape of the region which can be designated is inevitably limited to a rectangle. In addition, it is inconvenient that a color discriminating means is required to detect the L-shaped indication of the predetermined color.
In view of the above described background of the art, an apparatus was previously proposed in a Japanese Laid-Open Patent Application No. 62-159570 in which the applicant is the same as the assignee of the present application. According to the previously proposed apparatus, the desired region of the document is encircled by a marking made with a color felt pen and the like having a tone which falls within a predetermined tone range. When the document having such a marked region is read, the marked region is detected as the desired region of the document. In this case, the marked region including the marking is subjected to the image processing such as the trimming and masking. For this reason, when the marking is made with a pen of a relatively high tone, there is a problem in that the marking itself is thinly copied in the case where the image processing apparatus is applied to the copying machine. In the case where the image processing apparatus is applied to the facsimile machine, the marking itself thinly appears on a print which is outputted from a receiving facsimile machine. In other words, the marking itself appears in a processed image which is derived from the document image.